In highly trained and elite athletes, beetroot nitrate gave mixed results: across 31 small randomised trials mapped by a scoping review, some reported better cycling time trials, Yo-Yo test distance, sprint power or jump height and many found no significant difference, often despite large rises in blood nitrate and nitrite; in cycling time trials three of six trials were positive. A count of trial verdicts with no quality appraisal and no pooled estimate, so it cannot say whether nitrate works or by how much. Read in full
Main caveat: Scoping review: no risk-of-bias or certainty appraisal and no pooled estimates, by design.
Cherappurath and colleagues (India, Turkey, Romania) set out to map randomised trials of beetroot-derived nitrate in athletes of national level and above, because benefits seen in recreational and moderately trained people may not hold at the top.
Three databases gave 1,102 records, 568 after duplicates; of 105 full texts, 49 were excluded because the athletes were not highly trained or elite and 12 because the product had several ingredients, leaving 31 trials.
Doses ran from 4 to 19.5 mmol of nitrate a day (248-1,209 mg), most often 6.4-12.8 mmol; most trials gave one dose 2-3 h before testing and some loaded for 3-15 days.
The authors list positive results for cycling time trials, the Yo-Yo intermittent recovery test, anaerobic power, jump and other neuromuscular measures, exercise tolerance and recovery, and inconsistent ones for endurance, sport-specific skills, oxygen uptake and perceived exertion, while blood or saliva nitrate and nitrite rose wherever the table reports them.
They suggest that dose, duration, sport and training status shape the response, and conclude that nitrate may help these athletes, mainly in high-intensity and anaerobic efforts, but that the effects are inconsistent.
Our reading: the table shows more null than positive trials in most outcome families, every trial is small, and without appraisal or pooling the review shows where trials exist, not whether nitrate works.
Participants
31 trials, 8 to 80 athletes each (most under 20); ages 15-40 across trials; sex: 23 trials men only, 3 women only (water polo, field hockey, rugby), 5 both sexes (two in swimming, winter triathlon, short-track speed skating, cross-country skiing). Total participants and sex split are not given.
Sports: cycling 6 trials (the most of any sport), athletics, rowing, triathlon, cross-country skiing, swimming, football, rugby, handball, field hockey, water polo, tennis, taekwondo, short-track speed skating, alpine skiing.
Eligibility: McKay Tier 3-5 shown by competition level, rankings or professional status; mixed samples without separable data excluded.
Protocol
Search: keywords for beetroot or Beta vulgaris, athletes or sport or exercise, and randomised trials; reference lists screened; grey literature excluded; two screeners and a third to settle disagreements; two extractors.
Inclusion: randomised crossover or parallel trials against placebo or control; beetroot nitrate in any form as the only active ingredient, single dose or repeated; at least one exercise performance, recovery or physiological outcome.
Exclusion: non-beetroot nitrate salts, multi-ingredient products, non-randomised designs, non-English papers (2 excluded), 2 papers not retrievable.
Appraisal and synthesis: none of risk of bias or certainty (stated as outside a scoping review's aim); narrative and tabular charting by outcome family; no effect sizes.
Funding and interests: no external funding; no conflicts of interest declared. The funding of the included trials, and whether manufacturers supplied products or placebos, is not reported; the product named in most trials is a commercial concentrate (Beet It), with matched nitrate-depleted placebos from the same maker in several.
Key Results
How the trials came out, by the review's grouping (our count from its Table 2 and text):
| Outcome family | Reported improvement | No significant effect |
|---|---|---|
| Time trials (all sports) | 5: cycling 4-km and 16.1-km (+2.8%, +2.7%; 6.2 mmol, one dose), cycling 10-km (about 1.6% more power, 0.6% faster; 12.4 mmol/day for 7 days), cycling 4-km (−0.7% time; about 4 mmol/day for 8 days), rowing 2,000 m (about 4 s; 12.8 mmol, one dose), rowing 2,000 m (8.4 mmol improved it, 4.2 mmol did not) | 4 named by the review: cycling repeated 4-min trials (no gain, second trial slightly worse), cycling about 1 h (8.72 mmol, one dose), swimming 200 m, running 1,500 m; the table adds cycling 4-km in the heat, 1,000-m roller-ski and 1,000-m speed-skating trials with no change |
| Cycling time trials only | 3 of 6 | 3 of 6 |
| Exercise tolerance (time to exhaustion) | 2: winter triathletes (cycling at 85% of peak power; 19.5 mmol/day for 7 days), runners (6.5 mmol/day for 15 days) | taekwondo-specific test; supramaximal cycling bouts |
| Intermittent running (Yo-Yo IR1, Cooper test) | Yo-Yo +3.4% in footballers (12.9 mmol/day for 6 days); Cooper distance about +5% only in players with habitual nitrate intake under 4.84 mmol/day | prone Yo-Yo in rugby players |
| Anaerobic power, sprint | Wingate peak power about +11% and mean power about +7% (12.8 mmol); morning Wingate decline abolished; box jumps +7.6%, wall-sit +27.9% (8.9 mmol) | tennis, swimming, field hockey, taekwondo, handball sprints |
| Jump and strength | jump height in women's rugby (12.8 mmol) and men's handball (6.4 mmol for 3 days); handgrip +7.8% in handball | tennis, field hockey, rugby handgrip and sprint |
| Oxygen cost, economy | lower VO2, RER and lactate at the highest running speed in winter triathletes; better power per unit of oxygen in one cycling trial | two trials the review files as running (one is roller-skiing in its table), triathletes, cyclists |
| Recovery, soreness | soreness 22-38% lower at 12-48 h in alpine skiers; post-exercise muscle oxygenation in footballers | swimmers' recovery measures |
Dose: 4-19.5 mmol/day (248-1,209 mg); commonly 6.4-12.8 mmol (397-794 mg). The only within-trial dose comparisons: in rowers 8.4 mmol improved a 2,000-m trial and 4.2 mmol did not; in taekwondo 6.4 and 12.9 mmol both did nothing for performance, and the higher dose brought more gut symptoms.
Timing: mostly one dose 2-3 h before exercise, which the authors tie to the peak in plasma nitrite; loading of 3-15 days in several trials. Within one cycling trial, taking the dose 150 or 75 min before, or topping up, gave no benefit.
Who responds: not analysed. The authors suggest highly trained athletes respond less, citing their efficient aerobic systems; the one subgroup in the table is habitual dietary nitrate (benefit only below 4.84 mmol/day, with too few high-intake players to test), and one 1,500-m trial found 2 of 8 runners improved.
Side effects: more gut upset in women's rugby and with 12.9 mmol in taekwondo; red urine in handball.
Internal inconsistency: the winter-triathlon trial's dose is 19.5 mmol/day in the table but 6.5 mmol in the text.
Practical Application
For a national- or international-level athlete, beetroot nitrate is a maybe with no known size: in every outcome area some trials found a benefit and others no significant difference (cycling time trials 3 of 6), and no trial was appraised for quality. It does not change the base's position (SYNTH-67).
Where it differs from the guide: SYNTH-67 lists nitrate for time-trial speed under skip or low priority for road races and time trials over about 12 min, on a pooled time-trial effect of about zero (REF-3493, SMD −0.03 over 42 comparisons); the guide's athlete-only meta-analysis (REF-1695) did not pool time trials.This review lists cycling time trials among the outcomes most often improved; its own table shows 3 of 6 cycling time trials positive and 3 null, a vote count with no effect size, so it is not evidence against the guide's pooled result.
If an athlete wants to try it (practice, labelled): the trials mostly used a concentrate with 6.4-12.8 mmol (about 400-800 mg) of nitrate 2-3 h before the effort, sometimes after 3-15 days of daily doses; trial it in training first, as SYNTH-67 does for every supplement, and expect gut upset in some at the higher doses.
Who responds is unknown. Inference, not tested here: athletes whose usual diet is low in nitrate (few leafy greens or beetroot) may be the likelier responders, on one trial's subgroup; the authors' claim that elite athletes respond less was not tested within this review.
Limitations
Scoping review: no risk-of-bias or certainty appraisal and no pooled estimates, by design; conclusions rest on counting significant and non-significant trials, which ignores effect sizes and, with trials this small, can miss a small real effect as easily as it can count a chance positive.
Small trials (most under 20), mostly men, mostly single doses; the outcome families mix very different tests.
The abstract's ranking of positive outcomes (cycling time trials first) is not borne out by the review's own table, where nulls are as common.
The claim that results depend on dose, duration, sport and training status is the authors' suggestion; it was not analysed, and all included athletes were of similar tier by design.
Funding of the included trials and any manufacturer involvement are not reported; most trials used one commercial product, with placebos from the same maker in several.
English, peer-reviewed papers from three databases only; two papers not retrieved; one dose reported inconsistently between table and text.
No external funding for the review and no conflicts declared.
How this entry was checked and changed
Why this level
a systematic search of randomised trials, most of them crossovers of under 20, but as a scoping review it appraised none of them and pooled nothing, so its conclusions are a tally of conflicting trial verdicts